Water-based compositions are used in many industrial processes to help cool or clean metal components of industrial or residential equipment, shipping containers, plumbing and fixtures, buildings, land-based transportation systems, marine-based systems or habitats, or aeronautical systems or habitats. Water also may be a part of a solvent or other constituent of compositions that are being transported, processed, or otherwise handled by such items. Many types of metal components in such systems may contact water-based compositions including heat exchangers, pipes, tanks, valves, water pumps, pump impellers, propellers, and turbine plates, housings, work surfaces, fasteners, supports, computer components, hardware, etc. Metals include pure metals, alloys, intermetallic compositions, or other metal-containing compositions that are susceptible to corrosion.
Water-based compositions, for example, those that are used as heat exchange media, may damage metal components by causing erosion or corrosion of the metal. Corrosion generally is a destructive attack on metal involving oxidation or other chemical attack. For example, the presence of certain ions and biocides can increase oxidation and thereby accelerate the erosion or corrosion of items at risk.
Corroded metal components can have reduced functionality, causing inefficiencies or inoperability of the industrial process. Corroded components may need to be discarded, repaired or replaced. In addition, corrosion products accumulate and may decrease the rate of heat transfer between the corroded material and the water or other fluid media. Therefore, corrosion may reduce the efficiency of the system operation where efficient cooling is a factor. Corrosion of metallic components in industrial plants can cause system failures and even plant shutdowns.
The corrosion can also lead to the undesirable release of copper in the water-based composition. Dealing with the used water-based composition can also be problematic, especially for large volume industrial systems.
Triazole-based compounds have been used to inhibit corrosion of copper surfaces in industrial processes. Triazole-based corrosion inhibitors can form a film on a copper surface to protect against the damaging components of the aqueous composition. Triazole-based compounds such as benzotriazole and tolyltriazole are known copper corrosion inhibitors (see, for example, U.S. Pat. No. 4,675,158). U.S. Pat. No. 4,744,950 discloses the use of lower (e.g., C3-C6 linear alkyl, especially n-butyl) alkylbenzotriazoles as corrosion inhibitors in an aqueous system.
However, the preparation and use of triazole compounds can be problematic. For example, triazole performance is adversely affected in the presence of halogenated biocidal additives (e.g. hypochlorites). Also, tolyltriazole which is commonly used as a corrosion inhibitor for copper and copper alloys is manufactured from intermediates of the toluene nitration process for the preparation of toluene diamines which are used for the synthesis of toluene diisocyanate (TDI). These intermediates can be undesirable to work with and could potentially be non sustainable.